A variety of products utilize and/or rely upon a hydrophilic or hydrophobic material to increase fluid transport. For example, medical devices (e.g., medical diagnostic sensors, bandages, wound dressings, etc.), general chemical analyte sensors (e.g., water analysis sensors) or devices which are used in a wet and/or moist environment and function via capillary action often contain a hydrophilic material which has been deposited in or placed on at least a portion of the device/product in order to increase the fluid transfer properties thereof.
Generally, one problem that arises in such devices/products is that at least one extra production step must be used to place the hydrophilic or hydrophobic material in the desired place(s) in or near the portion of the device where increased hydrophilicity or hydrophobicity is desired. For example, in a closed capillary space used to transport fluid, the hydrophilic or hydrophobic material is generally deposited somewhere near the capillary opening or on a surface of the capillary space in order to facilitate better fluid transport.
The devices are often subjected to a desiccation step during the manufacture or during their transport. The desiccation removes the moisture from the hydrophilic materials. Moisture may interfere with the device's ability to give reliable and accurate test results. Hydrophilic materials often lose their ability to promote fluid transport.
Another problem that arises is that the hydrophilic or hydrophobic material needs to be stable so that the hydrophilic or hydrophobic material can offer fast and reliable transport of a variety of fluids across its surface, even after being stored for long periods of time (e.g., more than 3 months).